Neil Armstrong, the subject of the new BBC documentary “Being Neil Armstrong,” became a celebrity following his historic walk on the moon, partly because of his poetic words: “One small step for [a] man, one giant leap for mankind.”

But after doing what was required of him—a worldwide tour with fellow crew members Michael Collins and Buzz Aldrin to promote the Apollo 11 landing—Armstrong chose a far less public career as a teacher.

“And he didn't want to profit from it financially,” Smith added, “even though a lot of the other Moon walkers have done—and amazingly he's stood by that.”

Indeed, Buzz Aldrin has become “the face of space,” according to the BBC, “courting media attention with a series of high-publicity manoeuvres” that Armstrong might deem distasteful to do himself. But Aldrin’s work is just part of a story NASA is telling in an attempt to revamp its image, which today pales in comparison to the glory days of the Apollo 11.

Armstrong’s famous words may have helped define his celebrity, but the words also shine a light on his personality. In an interview with “60 Minutes,” Armstrong said he thought of the words because “I thought about all those 400,000 people that had given me the opportunity to make that step and thought ‘It's going to be a big something for all those folks and, indeed, a lot of others that even weren't even involved in the project.’”

In the modern sense, “celebrity” suggests a person has not only become famous, but embraced the fame, appearing in high-profile places and not shying away from tabloids, which appear to reinforce his or her relevance. A person like Neil Armstrong, on the other hand, may have been celebrated, but had no interest in making a highly profitable career out of his fame.

The legendary Paul Newman, an Armstrong contemporary, used his money to retreat from the spotlight and pursue a very different career. As The Montreal Gazette’s Bill Brownstein wrote in an obituary, “Newman was a mega movie star. He was an even more-mega mensch. He gave back.”

The profits from Newman’s Own, a company that Newman co-founded in 1986 that makes foods such as salad dressings, popcorn, cookies and sauces, has donated “more than $200 million to charities around the globe,” according to Brownstein. While running this company, Newman lived a private life on a farm in Connecticut.

“To Kill A Mockingbird” author Harper Lee, another contemporary of Armstrong, has the credentials to be a celebrity, but has also chosen to remain out of the spotlight since the publication of her seminal (and only) novel in 1960. It won the Pulitzer Prize and spoke of important issues including racial tolerance and social justice.

“I said what I had to say,” Lee said in explaining her decision to live out a private life. In effect, the book keeps speaking, though fans undeniably wish Lee would publish more.

As Charles J. Shields, a former schoolteacher and author of “Mockingbird: A Portrait of Harper Lee,” notes in an interview with The Christian Science Monitor, “In our era of relentless and often prurient self-exposure by some approval-hungry personalities, Lee prefers self-respect.”

In the Los Angeles Times, Scott Timberg writes that whether someone is a reclusive author, actress or pianist, it “can come off as arrogance, sensitivity, or a noble dissent— a high-minded refusal to engage with America's culture of celebrity, erosion of privacy and self-promotion.” For authors, it appears to be “wishful fantasy that their books might arrive unmediated, might ‘speak for themselves.’”

“Everybody wants to be famous now,” Lee Siegel, author of “Against the Machine: Being Human in the Age of the Electronic Mob,” explained to Timberg. “And a writer, especially, needs to keep his interiority detached. While someone like Paris Hilton doesn't have interiority, so she can put herself up for sale.”

Siegel alludes to a key factor in celebrity lifestyle choices: age. But some younger celebrities have successfully followed in the footsteps of predecessors like Paul Newman. For instance, Johnny Depp’s public appearances are rare and appear full of conscience. He recently visited sick children at a London hospital dressed as Captain Jack Sparrow, his character from “Pirates of the Caribbean.”

The hospital had treated Depp’s daughter when she was suffering from kidney failure and Depp reportedly donated $1.5 million to the hospital last year, Amy Wilkinson wrote for Hollywood Crush, an MTV blog.

Some suggest that the paparazzi are perpetuating a level of celebrity that some stars don’t even want. Last year Los Angeles City Councilman Dennis Zine proposed a law that would protect celebrities from “aggressive paparazzi,” The Associated Press reported. But L.A. Police Chief William Bratton suggested that the paparazzi don’t need those restrictions because the subjects of the photos were behaving themselves, thus causing less frenzy.